T. OKADA 



INTRODUCTION 



Through the recommendation of Dr. E. B. Basden, Institute of Animal Genetics, 

 Edinburgh, the author was enabled to examine a large collection of Cryptochaetidae, 

 Diastatidae and Drosophilidae from East Nepal, collected by Mr. R. L. Coe while a 

 member of the British Museum East Nepal Expedition, Sept. 1961-Febr. 1962. 

 The collection is made up of the following fifteen genera : Cryptochaetum (1 sp.) of 

 Cryptochaetidae, Diastata (2), Campichoeta (1) and Apsinota (2) of Diastatidae, and 

 Stegana (1), Leucophenga (16), Microdrosophila (6), Lissodrosophila (i), Hypselothyrea 

 (1), Liodrosophila (4), Paramycodrosophila (1), Chaetodrosophilella (1), Scaptomyza (4), 

 Diathoneura (1) and Drosophila (34) of Drosophilidae. 



The genus Lissodrosophila and thirty-seven species belonging to ten genera are 

 described as new : Diastata (1 sp. n.), Apsinota (1), Leucophenga (4), Microdrosophila 

 (5), Lissodrosophila (1), Liodrosophila (3), Chaetodrosophilella (1), Scaptomyza (3), 

 Diathoneura (1) and Drosophila (17). 



These genera have apparently not been recorded from Nepal, apart from Droso- 

 phila, of which the following six species were recorded earlier by the present author 

 (Okada, 1955) : D. bipectinata Duda, D. kikkawai Burla, D. melanogaster Meigen, 

 D. takahashii Sturtevant, D. nepalensis Okada and D. immigrans Sturtevant. Of 

 these, D. bipectinata alone is not recorded in the present collection, which has 

 brought the number of Nepalese species of the three families involved to seventy- 

 seven. 



The drosophilid fauna of Nepal is most interesting biogeographically and ecologi- 

 cally, as it comprises Palaearctic and Oriental elements ranging from low, subtropical 

 lands to the highest mountains in the world. In this respect, it closely resembles the 

 pattern of the Japanese fauna, which is, though essentially Palaearctic, rich in 

 Oriental elements, as for example with the mosquitoes (Edwards, 192 1 : 264). In 

 addition to describing new forms, some of the poorly-known species are re-described 

 in the light of current taxonomic knowledge. 



Some taxonomic characters are explained below. 



Width of front at its posterior margin : measured across the ocellar triangle. 



Width of cheek : the greatest distance from eye margin measured vertically to the 

 tangent drawn upon eye margin. 



Wing indices : C-index (costal index), a ratio in length of the second and the 

 third costal sections ; 4"V-index (4th vein index), a ratio in length of the distal and 

 the proximal sections of the vein M (media) ; 4C-index, a ratio in length of the 

 third costal section and the proximal section of M ; 5x-index, a ratio in length of the 

 distal section of the vein Cu (cubitus) and the posterior crossvein ; Ac-index (acro- 

 costal index, Burla, 1956 : 193), a ratio in length of the third and fourth costal 

 sections. 



Ci-bristles : strong bristles at the end of the first costal section. 



C^-fringe : the portion of the third costal section bearing the strong costal fringe 

 (Wheeler and Takada, 1964 : 168). 



Sterno-index : a ratio in length of the anterior and the ventral (posterior, Kikkawa 



